首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1299522篇
  免费   101670篇
  国内免费   2011篇
耳鼻咽喉   18711篇
儿科学   45132篇
妇产科学   35590篇
基础医学   184886篇
口腔科学   34070篇
临床医学   114298篇
内科学   262313篇
皮肤病学   28268篇
神经病学   102605篇
特种医学   51934篇
外国民族医学   660篇
外科学   199194篇
综合类   27583篇
现状与发展   1篇
一般理论   420篇
预防医学   98426篇
眼科学   28352篇
药学   96482篇
  4篇
中国医学   2450篇
肿瘤学   71824篇
  2018年   13478篇
  2017年   10224篇
  2016年   11200篇
  2015年   12705篇
  2014年   17684篇
  2013年   27013篇
  2012年   37015篇
  2011年   39170篇
  2010年   23421篇
  2009年   22267篇
  2008年   37599篇
  2007年   40308篇
  2006年   40565篇
  2005年   39417篇
  2004年   38582篇
  2003年   37291篇
  2002年   36599篇
  2001年   64631篇
  2000年   67197篇
  1999年   56935篇
  1998年   15346篇
  1997年   13952篇
  1996年   14370篇
  1995年   13632篇
  1994年   12924篇
  1993年   11934篇
  1992年   45038篇
  1991年   43939篇
  1990年   42662篇
  1989年   40553篇
  1988年   37349篇
  1987年   36640篇
  1986年   34056篇
  1985年   32670篇
  1984年   24470篇
  1983年   20617篇
  1982年   11939篇
  1981年   10899篇
  1980年   9702篇
  1979年   21679篇
  1978年   15072篇
  1977年   12755篇
  1976年   11880篇
  1975年   12804篇
  1974年   14902篇
  1973年   14328篇
  1972年   13144篇
  1971年   11920篇
  1970年   11227篇
  1969年   10198篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
In the 6th Basic Plan for Long-Term Electricity Supply and Demand (6th BPE) for Korea, for the first time, the environmental costs of air pollution caused by oxides of sulfur (SOx), oxides of nitrogen (NOx), and particulate matters (PM) from power plants were estimated and included. However, several deficiencies in evaluating the environmental costs were found. In this study, (1) the validity of the environmental costs used in the 6th BPE was assessed, (2) a systematic approach was suggested and used to improve the environmental costs estimation, and (3) the sensitivity of the cost of generating electricity to the environmental costs by fuel type with the proposed approach was discussed. We found that the applied environmental costs used in the 6th BPE did not fully include the demographic characteristics of Korea. By applying more realistic parameter values, it was found that the newly estimated environmental cost was about 23 times higher than the cost estimated in the original 6th BPE for coal-fired power plants and about 1.5 times higher for liquefied natural gas (LNG)-fired power plants, suggesting that LNG-fired power plants are more economical if using more realistic environmental costs. Thus, it is critical to check the validity of parameter values when calculating environmental costs.  相似文献   
62.
63.
64.
65.
66.
67.
This study used the National Survey of Ambulatory Surgery (NSAS) database to measure the incidence of and risk factors for symptoms in the ambulatory surgery center and problems within 24 h after isolated carpal tunnel release (CTR). The NSAS contained records on 400,000 adult patients with carpal tunnel syndrome who were treated with CTR in 2006, based on ICD-9 codes. The type of anesthesia used and factors associated with symptoms and problems were sought in bivariate and multivariable statistical analyses. The mean duration of the procedure was 16 ± 8.8 min. Only 5 % were performed under local anesthesia without sedation, 45 % with IV sedation, 28 % regional anesthesia, and 19 % general anesthesia. Symptoms in the ambulatory surgery center or a problem within 24 h after discharge were recorded in 10 % of patients, all of them minor and transient, including difficulties with pain and its treatment. The strongest risk factors were male sex, age of 45 years and older, and participation of an anesthesiologist. Local anesthesia and regional anesthesia were associated with more perioperative symptoms and postoperative problems. Most CTR are performed with some sedation in the United States. CTR is a safe procedure: one in 10 patients will experience a minor issue in the perioperative or immediate postoperative period.  相似文献   
68.
Background Immune checkpoint blockers (ICBs) activate CD8+ T cells, eliciting both anti-cancer activity and immune-related adverse events (irAEs). The relationship of irAEs with baseline parameters and clinical outcome is unclear.Methods Retrospective evaluation of irAEs on survival was performed across primary (N = 144) and secondary (N = 211) independent cohorts of patients with metastatic melanoma receiving single agent (pembrolizumab/nivolumab—sICB) or combination (nivolumab and ipilimumab—cICB) checkpoint blockade. RNA from pre-treatment and post-treatment CD8+ T cells was sequenced and differential gene expression according to irAE development assessed.Results 58.3% of patients developed early irAEs and this was associated with longer progression-free (PFS) and overall survival (OS) across both cohorts (log-rank test, OS: P < 0.0001). Median survival for patients without irAEs was 16.6 months (95% CI: 10.9–33.4) versus not-reached (P = 2.8 × 10−6). Pre-treatment monocyte and neutrophil counts, but not BMI, were additional predictors of clinical outcome. Differential expression of numerous gene pathway members was observed in CD8+ T cells according to irAE development, and patients not developing irAEs demonstrating upregulated CXCR1 pre- and post-treatment.Conclusions Early irAE development post-ICB is associated with favourable survival in MM. Development of irAEs is coupled to expression of numerous gene pathways, suggesting irAE development in-part reflects baseline immune activation.Subject terms: Immunotherapy, Melanoma  相似文献   
69.
70.
Jahn  P. 《Der Onkologe》2020,26(11):1040-1046
Die Onkologie - Die Pflegepersonaluntergrenzen als rote Linien zur Abgrenzung einer gefährlichen Pflegepraxis sind nicht geeignet, die dringend benötigte Trendwende einzuleiten und...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号